feat(rm): new post_remove hook

Provides an item after it has been removed from the library.

docs/developers/api/hooks.core.rst

@@ -23,3 +23,8 @@ Import
 ------
 .. autoclass:: moe.plugins.moe_import.import_core.Hooks
    :members:
+
+Remove
+------
+.. autoclass:: moe.plugins.remove.rm_core.Hooks
+   :members:

moe/plugins/remove/rm_cli.py

@@ -45,4 +45,4 @@ def _parse_args(config: Config, args: argparse.Namespace):
         raise SystemExit(1)
 
     for item in items:
-        moe_rm.remove_item(item)
+        moe_rm.remove_item(config, item)

moe/plugins/remove/rm_core.py

@@ -2,17 +2,38 @@
 
 import logging
 
-from moe.config import MoeSession
+import pluggy
+
+import moe
+from moe.config import Config, MoeSession
 from moe.library.lib_item import LibItem
 
 __all__ = ["remove_item"]
 
 log = logging.getLogger("moe.remove")
 
 
-def remove_item(item: LibItem):
+class Hooks:
+    """Remove plugin hook specifications."""
+
+    @staticmethod
+    @moe.hookspec
+    def post_remove(config: Config, item: LibItem):
+        """Provides an item after it has been removed from the library."""
+
+
+@moe.hookimpl
+def add_hooks(plugin_manager: pluggy.manager.PluginManager):
+    """Registers `add` hookspecs to Moe."""
+    from moe.plugins.remove.rm_core import Hooks
+
+    plugin_manager.add_hookspecs(Hooks)
+
+
+def remove_item(config: Config, item: LibItem):
     """Removes an item from the library."""
     session = MoeSession()
 
     log.info(f"Removing '{item}' from the library.")
     session.delete(item)
+    config.plugin_manager.hook.post_remove(config=config, item=item)

tests/plugins/remove/test_rm_cli.py

@@ -31,7 +31,7 @@ def test_track(self, mock_track, mock_query, mock_rm, tmp_rm_config):
         moe.cli.main(cli_args, tmp_rm_config)
 
         mock_query.assert_called_once_with("*", query_type="track")
-        mock_rm.assert_called_once_with(mock_track)
+        mock_rm.assert_called_once_with(tmp_rm_config, mock_track)
 
     def test_album(self, mock_album, mock_query, mock_rm, tmp_rm_config):
         """Albums are removed from the database with valid query."""
@@ -41,7 +41,7 @@ def test_album(self, mock_album, mock_query, mock_rm, tmp_rm_config):
         moe.cli.main(cli_args, tmp_rm_config)
 
         mock_query.assert_called_once_with("*", query_type="album")
-        mock_rm.assert_called_once_with(mock_album)
+        mock_rm.assert_called_once_with(tmp_rm_config, mock_album)
 
     def test_extra(self, mock_extra, mock_query, mock_rm, tmp_rm_config):
         """Extras are removed from the database with valid query."""
@@ -51,7 +51,7 @@ def test_extra(self, mock_extra, mock_query, mock_rm, tmp_rm_config):
         moe.cli.main(cli_args, tmp_rm_config)
 
         mock_query.assert_called_once_with("*", query_type="extra")
-        mock_rm.assert_called_once_with(mock_extra)
+        mock_rm.assert_called_once_with(tmp_rm_config, mock_extra)
 
     def test_multiple_items(
         self, mock_track_factory, mock_query, mock_rm, tmp_rm_config
@@ -64,7 +64,7 @@ def test_multiple_items(
         moe.cli.main(cli_args, tmp_rm_config)
 
         for mock_track in mock_tracks:
-            mock_rm.assert_any_call(mock_track)
+            mock_rm.assert_any_call(tmp_rm_config, mock_track)
         assert mock_rm.call_count == 2
 
     def test_exit_code(self, mock_query, mock_rm, tmp_rm_config):

tests/plugins/remove/test_rm_core.py

@@ -1,47 +1,84 @@
 """Test the core api of the ``remove`` plugin."""
 
+import pytest
+
+import moe
+from moe.config import Config, ExtraPlugin
 from moe.library.album import Album
 from moe.library.extra import Extra
+from moe.library.lib_item import LibItem
 from moe.library.track import Track
 from moe.plugins import remove as moe_rm
 
 
+@pytest.fixture
+def tmp_rm_config(tmp_config) -> Config:
+    """A temporary config for the edit plugin with the cli."""
+    return tmp_config('default_plugins = ["remove"]', tmp_db=True)
+
+
+class RemovePlugin:
+    """Test plugin that implements the remove hookspecs."""
+
+    @staticmethod
+    @moe.hookimpl
+    def post_remove(config: Config, item: LibItem):
+        """Apply the new title onto the old album."""
+        if isinstance(item, Track):
+            item.title = "removed"
+
+
 class TestRemoveItem:
     """Tests `remove_item()`."""
 
-    def test_track(self, mock_track, tmp_session):
+    def test_track(self, mock_track, tmp_session, tmp_rm_config):
         """Tracks are removed from the database with valid query."""
         tmp_session.add(mock_track)
         tmp_session.flush()
 
-        moe_rm.remove_item(mock_track)
+        moe_rm.remove_item(tmp_rm_config, mock_track)
 
         assert not tmp_session.query(Track).scalar()
 
-    def test_album(self, mock_album, tmp_session):
+    def test_album(self, mock_album, tmp_session, tmp_rm_config):
         """Albums are removed from the database with valid query.
 
         Removing an album should also remove any associated tracks and extras.
         """
         mock_album = tmp_session.merge(mock_album)
         tmp_session.flush()
 
-        moe_rm.remove_item(mock_album)
+        moe_rm.remove_item(tmp_rm_config, mock_album)
 
         assert not tmp_session.query(Album).scalar()
         assert not tmp_session.query(Track).scalar()
         assert not tmp_session.query(Extra).scalar()
 
-    def test_extra(self, mock_extra, tmp_session):
+    def test_extra(self, mock_extra, tmp_session, tmp_rm_config):
         """Extras are removed from the database with valid query."""
         tmp_session.add(mock_extra)
         tmp_session.flush()
 
-        moe_rm.remove_item(mock_extra)
+        moe_rm.remove_item(tmp_rm_config, mock_extra)
 
         assert not tmp_session.query(Extra).scalar()
 
 
+class TestPostRemove:
+    """Test the `post_remove` hookspec."""
+
+    def test_post_add(self, mock_track, tmp_config):
+        """Ensure plugins can implement the `pre_add` hook."""
+        config = tmp_config(
+            "default_plugins = ['remove']",
+            extra_plugins=[ExtraPlugin(RemovePlugin, "remove_plugin")],
+        )
+
+        config.plugin_manager.hook.post_remove(config=config, item=mock_track)
+
+        assert mock_track.title == "removed"
+
+
 class TestPluginRegistration:
     """Test the `plugin_registration` hook implementation."""